<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://cdn.bootcss.com/jquery/1.12.4/jquery.min.js"></script>
    <script src="cyb.js"></script>
</head>
<body>
    <a class="js-download" href="javascript:;">下载</a>
    <form>
        <input type="checkbox" name="num" value="1"/>1<br/>
        <input type="checkbox" name="num" value="2"/>2<br/>
        <input type="checkbox" name="num" value="3"/>3<br/>
        <input type="checkbox" name="num" value="4"/>4
    </form>
</body>
</html>